The present invention relates to a lens system and an imaging apparatus that uses such lens system.
Japanese Laid-Open Patent Publication No. 2003-232993 (hereinafter simply “Document 1”) discloses the provision of a refractive optical system that forms an intermediate image and is capable of maintaining a favorable image forming performance in spite of using a small number of lenses. To do so, Document 1 discloses a refractive optical system including a lens group that forms an intermediate image of a subject, a field lens group disposed in the periphery of the formation position of the intermediate image, and a relay lens group that reforms the intermediate image into another image, where the focal length f1 of the image forming group and the focal length f of the refractive optical system satisfy the condition “1<|f1/f|<3”.